Light source, device including light source, and/or methods of making the same

ABSTRACT

Certain example embodiments of this invention relate to techniques for improving the performance of Lambertian and non-Lambertian light sources. In certain example embodiments, this is accomplished by (1) providing an organic-inorganic hybrid material on LEDs (which in certain example embodiments may be a high index of refraction material), (2) enhancing the light scattering ability of the LEDs (e.g., by fractal embossing, patterning, or the like, and/or by providing randomly dispersed elements thereon), and/or (3) improving performance through advanced cooling techniques. In certain example instances, performance enhancements may include, for example, better color production (e.g., in terms of a high CRI), better light production (e.g., in terms of lumens and non-Lambertian lighting), higher internal and/or external efficiency, etc.

FIELD OF THE INVENTION

Certain example embodiments of this invention relate to light sources,devices including light sources, and methods of making the same. Moreparticularly, certain example embodiments of this invention relate totechniques for improving the performance (e.g., efficiency, color and/orlight production, etc.) of light sources that may be Lambertian ornon-Lambertian. In certain example embodiments, this is accomplished by(1) providing an organic-inorganic hybrid material on LEDs (which incertain example embodiments may be a high index of refraction material),(2) enhancing the light scattering ability of the LEDs (e.g., by fractalembossing, patterning, or the like, and/or by providing randomlydispersed elements thereon), and/or (3) improving performance throughadvanced cooling techniques.

BACKGROUND AND SUMMARY OF EXAMPLE EMBODIMENTS OF THE INVENTION

A large proportion (some estimates are as high as 25%) of theelectricity generated in the United States each year goes to lighting.Accordingly, there is an ongoing need to provide lighting that is moreenergy-efficient. It is well-known that incandescent light bulbs arevery energy-inefficient light sources. About 90% of the electricity theyconsume is released as heat rather than light. Fluorescent light bulbsare more efficient than incandescent light bulbs (e.g., by a factor ofabout 10) but are still less efficient as compared to solid state lightemitters, such as light emitting diodes.

In addition, as compared to the normal lifetimes of solid state lightemitters, e.g., light emitting diodes, incandescent light bulbs haverelatively short lifetimes, typically about 750-1,000 hours. Incomparison, light emitting diodes, for example, have typical lifetimesbetween 50,000 and 70,000 hours. Fluorescent bulbs have yet longerlifetimes (e.g., 10,000-20,000 hours) than incandescent lights, butprovide less favorable color reproduction.

Color reproduction is typically measured using the Color Rendering Index(CRI Ra), which is a relative measure of the shift in surface color ofan object when lit by a particular lamp. CRI Ra is a modified average ofthe measurements of how the color rendition of an illumination systemcompares to that of a reference radiator when illuminating eightreference colors. The CRI Ra equals 100 if the color coordinates of aset of test colors being illuminated by the illumination system are thesame as the coordinates of the same test colors being irradiated by thereference radiator. Daylight has a high CRI (Ra of approximately 100),with incandescent bulbs also being relatively close (Ra greater than95), and fluorescent lighting being less accurate (typical Ra of 70-80).Certain types of specialized lighting have very low CRI Ra. For example,mercury vapor or sodium lamps have Ra as low as about 40 or even lower.Another challenge facing the development of new lighting systems is howto achieve a high CRI.

Another issue faced by conventional light fixtures is the need toperiodically replace the lighting devices (e.g., light bulbs, etc.).Such issues are particularly problematic where access is difficult(e.g., vaulted ceilings, bridges, high buildings, traffic tunnels, etc.)and/or where change-out costs are extremely high. The typical lifetimeof conventional fixtures is about 20 years, corresponding to alight-producing device usage of at least about 44,000 hours (e.g., basedon usage of 6 hours per day for 20 years). Light-producing devicelifetime is typically much shorter, thereby creating the need forperiodic change-outs. Thus, a further challenge lies in achieving a longlifetime so as to reduce the amount of downtime.

Designs have been provided in which existing LED component packages andother electronics are assembled into a fixture. In such designs, apackaged LED is mounted to a circuit board mounted to a heat sink, andthe heat sink is mounted to the fixture housing along with requireddrive electronics. In many cases, additional optics (secondary to thepackage parts) are also needed to produce uniform illumination. Short ofthe optics, LEDS behave as point sources that fan out the light. LEDSespecially at the die level are Lambertian in nature.

The expression “light emitting diode” is sometimes used to refer to thebasic semiconductor diode structure (e.g., the chip). The commonlyrecognized and commercially available “LED” that is sold (for example)in electronics stores typically represents a “packaged” device made upof a number of parts. These packaged devices typically include asemiconductor based light emitting diode such as (but not limited to)those described in U.S. Pat. Nos. 4,918,487; 5,631,190; and 5,912,477(each incorporated herein by reference in its entirety), various wireconnections, and a package that encapsulates the light emitting diode.

In substituting light emitting diodes for other light sources, e.g.,incandescent light bulbs, packaged LEDs have been used with conventionallight fixtures, for example, fixtures that include a hollow lens and abase plate attached to the lens, the base plate having a conventionalsocket housing with one or more contacts that is/are electricallycoupled to a power source. For example, LED light bulbs that comprise anelectrical circuit board, a plurality of packaged LEDs mounted to thecircuit board, and a connection post attached to the circuit board andadapted to be connected to the socket housing of the light fixture,whereby the plurality of LEDs can be illuminated by the power source,have been constructed.

FIG. 1 is a molded, flexible silicone rubber untinted, diffused lightguide array 102 usable in connection with LED light sources. The FIG. 1example may be used, for example, in connection with-backlightingkeypads and indicator windows, e.g., in front panel assemblies.Differently sized and/or shaped light pipe elements 104, 106, and 108may be provided in the light guide array 102. LED lamps may fit againstthe bases of the solid light pipe elements 104, 106, and 108, or fitinside hollow light pipe elements. The light pipe array 102 may beplaced over an LED lamp PC board assembly to form a backlighting unit.

FIG. 2 is a simplified view of a LED lighted panel assembly 200. Thisinternally lighted panel uses HLMP-650X untinted, non-diffused, SMTsubminiature LED lamps 202 surface mounted on a double-sided PC board204. Maximum metalization is used on both sides to achieve a low thermalresistance to ambient, and metallization vias 206 are shown in FIG. 2.The LED lamps 202 are distributed throughout the panel (which includes aglass substrate 208) to achieve a desired lighting effect. Light raysfrom the LED lamps 202 blend together within the panel to produce asomewhat more even illumination through the illuminated areas on theface of the panel 200. These illuminated areas are diffused and coatedwith a thin layer of translucent white paint. In daylight, the LED lamps202 are off, and the illumination areas 210 appear white by reflectingambient light. At night, these areas are internally illuminated by theLED lamps 202 and appear the same color as the LED light. The exteriorsurfaces of the panel 200 are painted with a white reflecting paint,leaving open the areas on the face of the panel to be internallyilluminated. An overcoat of black, scratch resistant paint is added toform the exterior finish 212. The overall thickness of the panel is 5.84mm.

Although the development of light emitting diodes has in many waysrevolutionized the lighting industry, some of the characteristics oflight emitting diodes have presented challenges, some of which have notyet been fully met. For example, the emission spectrum of any particularlight emitting diode is typically concentrated around a singlewavelength (as dictated by the light emitting diode's composition andstructure), which is desirable for some applications, but not desirablefor others, e.g., for providing lighting, such an emission spectrumprovides a very low CRI Ra.

Thus, it will be appreciated that there is a need in the art for animproved light source/fixture that overcomes one or more of these and/orother difficulties, and/or method of making the same.

In certain example embodiments, a method of making a coated articleincluding a substrate supporting a coating is provided. A titanium-basedprecursor is provided. A chelate is provided. The titanium-basedprecursor is reacted with the chelate to form a chelatedtitanium-inclusive substance. An organic resin material is provided. Thechelated titanium-inclusive substance is cross-linked with the organicresin material to form an organic-inorganic hybrid solution. Theorganic-inorganic hybrid solution is disposed on the substrate informing the coating.

In certain example embodiments, a method of making a coated articleincluding a substrate supporting a coating is provided. Anorganic-inorganic hybrid solution is provided, with theorganic-inorganic hybrid solution having been made by: reacting atitanium- and/or zirconium-based precursor with a chelate to form achelated substance, and cross-linking the chelated substance with anorganic material to form the organic-inorganic hybrid solution. Either(a) the organic-inorganic hybrid solution is wet applied on thesubstrate, or (b) the organic-inorganic hybrid solution is introducedinto a carrier medium and then the carrier medium is extruded onto thesubstrate. The organic-inorganic hybrid solution is cured once disposedon the substrate.

In certain example embodiments, a method of making an electronic deviceis provided. A substrate is provided. At least one light emitting diode(LED) is disposed on the substrate. An organic-inorganic hybrid solutionis provided, with the organic-inorganic hybrid solution having been madeby: reacting a titanium- and/or zirconium-based precursor with a chelateto form a chelated substance, and cross-linking the chelated substancewith an organic material to form the organic-inorganic hybrid solution.Either (a) the organic-inorganic hybrid solution is wet applied on thesubstrate over the at least one LED, or (b) the organic-inorganic hybridsolution is introduced into a carrier medium and then the carrier mediumis extruded onto the substrate over the at least one LED. Theorganic-inorganic hybrid solution is cured once disposed on thesubstrate.

In certain example embodiments, a device is provided. A first substrateis provided. A mirror is supported by the first substrate. A printedcircuit board supports a plurality of light emitting diodes (LEDs)/Asecond substrate is provided. A laminate is supported by a first majorsurface of the second substrate that faces the printed circuit boardsupporting the plurality of LEDs. The laminate is formed from a firstorganic-inorganic hybrid solution, with the laminate having an index ofrefraction of at least about 1.8.

In certain example embodiments, a device is provided. A first glasssubstrate is provided. A thin-film mirror coating is supported by thefirst substrate. A flexible printed circuit (FPC) supports a pluralityof light emitting diodes (LEDs) flip-chip mounted thereto. A secondglass substrate is provided. A laminate is supported by a first majorsurface of the second substrate that faces the printed circuit boardsupporting the plurality of LEDs, with the laminate laminating togetherthe first and second substrates.

In certain example embodiments, a device is provided. A first glasssubstrate is provided. A thin-film mirror coating is supported by thefirst substrate. A flexible printed circuit (FPC) supports a pluralityof light emitting diodes (LEDs) flip-chip mounted thereto. Apolymer-based insulator layer is interposed between the mirror and theFPC, with the insulator layer being formed from a firstorganic-inorganic hybrid solution. A second glass substrate is provided.A laminate is supported by a first major surface of the second substratethat faces the printed circuit board supporting the plurality of LEDs,with the laminate laminating together the first and second substrates.

In certain example embodiments, a method of making an LED device isprovided. A substrate is provided. A plurality of LEDs is formed on thesubstrate. A random pattern is created on the LEDs and/or in one or morelayers of the LEDs, with the random pattern having a light scatteringeffect on light produced by the LEDs. In certain example embodiments, anLED device is provided.

According to certain example embodiments, the random pattern may becreated by: generating a fractal pattern, with the fractal pattern beinga random fractal pattern or having randomness introduced thereto; andtransferring the generated fractal pattern onto one or more layers ofthe LEDs.

According to certain example embodiments, the random pattern may becreated by: providing an aqueous solution of nano- or micron-scaleelements; and disposing the solution to an area, directly or indirectly,on the LEDs to randomly disperse the elements on the LEDs.

In certain example embodiments, a device is provided. First and secondglass substrates are provided, with the first and second substratesbeing substantially parallel and spaced apart so as to define a cavitytherebetween. A plurality of pillars is disposed between the first andsecond substrates. An edge seal is provided around the periphery of thefirst and/or second susbtrate(s). At least one conductive bus bar isdisposed on an inner surface of the second substrate facing the firstsubstrate. At least one n-leg and at least one p-leg is in contact withthe at least one bus bar. At least one conductor connects the at leastone n-leg and the at least one p-leg. At least one LED supported by theat least one conductor. In certain example embodiments, a method ofmaking the same is provided.

In certain example embodiments, a device is provided. First and secondglass substrates are provided, with the first and second substratesbeing substantially parallel and spaced apart so as to define a cavitytherebetween. A plurality of pillars is disposed between the first andsecond substrates. An edge seal is provided around the periphery of thefirst and/or second susbtrate(s). At least one conductive bus bar isdisposed on an inner surface of the second substrate facing the firstsubstrate. A plurality of thermoelectric (TE) modules is in contact withthe at least one bus bar, with each said TE module including an n-legand p-leg connected to one another via a conductor. A plurality of ILEDsis disposed on conductors of the plurality of TE modules. In certainexample embodiments, a method of making the same is provided.

The features, aspects, advantages, and example embodiments describedherein may be combined in any suitable combination or sub-combination torealize yet further embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages may be better and morecompletely understood by reference to the following detailed descriptionof exemplary illustrative embodiments in conjunction with the drawings,of which:

FIG. 1 is a molded, flexible silicone rubber untinted, diffused lightguide array usable in connection with LED light sources;

FIG. 2 is a simplified view of a LED lighted panel assembly;

FIG. 3 plots the percent transmittance versus wavelength for 0.30 um and0.23 um thick high index matching layers prepared from inorganic-organicpolymer matrix systems in accordance with certain example embodiments;

FIG. 4 is a flowchart illustrating an example process for making ahybrid high refractive index film in accordance with certain exampleembodiments;

FIG. 5 shows the basic formulation, cross-linking, and curing stepsinvolved in the FIG. 4 example process;

FIG. 6 plots the luminous efficacy of an AlGaAs diode with and withoutthe enhanced light scattering caused by the thin film fractal embossingof certain example embodiments;

FIG. 7 a is a flowchart illustrating an example process for helping toachieve non-Lambertian broad-band scattering useful in achieving a highCRI using fractal patterns in accordance with certain exampleembodiments;

FIG. 7 b is a flowchart illustrating an example process for helping toachieve non-Lambertian broad-band scattering useful in achieving a highCRI using scattering elements in accordance with certain exampleembodiments;

FIG. 8 is a cross-sectional view of a flat ILED matrix laminate inaccordance with certain example embodiments;

FIG. 9 is an illustrative ILED structure based on AlGaAs in accordancewith certain example embodiments;

FIG. 10 is a cross-sectional view demonstrating illustrative activecooling techniques for a flip-chip mounted LED array usingthermoelectric modules in accordance with certain example embodiments;

FIG. 11 is a plan view of an ILED structure electrically connected inseries and thermally connected in parallel in accordance with certainexample embodiments;

FIG. 12 is a cross-sectional view of a flip-chip sub-mount wafer inaccordance with certain example embodiments; and

FIG. 13 is an example VIG incorporating LEDs in accordance with anexample embodiment.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

Certain example embodiments relate to substantially flat solid statelighting based on two dimensional arrays of LEDS systems embedded orlaminated in glass for flat and/or curve manifolds, and/or methods ofmaking the same. In certain example embodiments, light out-couplingtechniques are used to make these light systems more efficient. Suchdevices may in certain example instances be run at low current densitiesthresholds, which consequently reduces heat issues. Currently inorganicLEDs (LEDS or ILEDS) are packaged individually in plastic (sometimesepoxy) packaging. LEDS are thus point sources whereby the intensity ofthe light varies inversely with the square of distance X cos Ω.Recently, there has been a trend to tile these LEDS in linear arrays forvarious systems where the light can be coupled to the edge of the glasssuch as in backlights for LCD TV panels. In such devices, specificdiffusers are used to couple the light out.

As is known, a Lambertian source is an optical source that obeysLambert's cosine law in that the radiance of the optical source isdirectly proportional to the cosine of the angle, with respect to thedirection of maximum radiance, from which the source is viewed. LEDsapproximate Lambertian sources because they tend to have a large beamdivergence and a radiation pattern that approximates a sphere. Certainexample embodiments may include Lambertian and/or non-Lambertian lightsources. In certain example embodiments, a Lambertian light source maybe achieved by providing a non-Lambertian light source with anout-coupling photometric diffuser (e.g., of or including acetal, silicondioxide, etc.) proximate to the non-Lambertian light source to achieve aLambertian or Lambertian-like effect. Although reference has been madeto Lambertian (and non-Lambertian) light sources, it will be appreciatedthat a light source may be considered Lambertian (or non-Lambertian)even though the light source is substantially Lambertian (orsubstantially non-Lambertian).

High efficiency light emitting diodes (LEDs) are desired for manyapplications such as, for example, displays, printers, short-haulcommunications, optoelectronic computer interconnects, etc.Unfortunately, however, there is a gap between the internal efficiencyof LEDs and their external efficiency. The internal quantum yield ofgood quality double heterostructures can exceed 99%. On the other hand,ordinary packaged LEDs are usually only a few percent efficient. Onereason for this shortfall is the difficulty of light escaping from highrefractive index semiconductors, e.g., because of the narrow escape conefor light. The escape cone for internal light in a semiconductor ofrefractive index of n=3.5 is only −16 degrees, as imposed by Snell'sLaw.

This narrow escape cone for spontaneous emission covers a solid angle ofΩ≈¼n_(s) ²×4π Steradians. A mere 2% of the internally generated lightcan escape into free space, with the rest suffering total internalreflection and risking re-absorption. A number of schemes have partiallyovercome this problem, based on the idea of coupling the light out ofdiode semiconductor by using a matching index hemispherical dome.However, short of that perfect match, the escape solid angle is Ω≈n_(c)²/4n_(s) ²×4π Steradians.

Most of the packaging used is plastic, which has a refractive index thatis much less than that of the semiconductor (nc<<ns). Epoxy is oftenused as the encapsulant, and its refractive index is still much lessthan GaAs and GaN, which are the materials often used for LEDs.

This formula is actually a general upper limit since it can be derivedby statistical mechanical phase-space arguments without reference to aspecific lens geometry. Therefore, it applies to inverse Winstonconcentrators and other types of optical schemes. For a matchingrefractive index, the “lens” structure may be a thick, transparent,semiconductor layer, which may sometimes add to the cost. The presentstate-of-the-art is −30% external efficiency in AlGaAs-based LEDs thatemploy a thick transparent semiconductor superstrate, and totalsubstrate etching in a particularly low-loss optical design. One way toincrease the escape probability is to give the photons multipleopportunities to find the escape cone.

Certain example embodiments involve bare LED arrays that are de-bondedfrom a substrate or provided in a flip-chip format. For instance,certain example embodiments may involve debonding thin-film LEDs fromtheir substrates (e.g., by epitaxial lift-off) and tiling them in linearand two dimensional arrays onto a glass substrate that has already beencoated with conductive bus bars. Certain example embodiments may involvedirectly mounting LEDs onto a flexible PCB. Such a PCB may be bonded toa glass substrate that has a conductive coating to aid in dissipatingheat. The LED array may be overcoated with a transparent, highrefractive index layer. Such example arrangements advantageously make itmuch easier for light to escape from the LED structure, thereby reducingabsorption. In certain example embodiments, by nano-texturing thethin-film surface using various techniques, the light ray dynamicsbecomes chaotic, and the optical phase-space distribution becomes“ergodic,” allowing even more of the light to find the escape cone.Simulations of such example techniques have demonstrated at least 30%external efficiency in GaAs LEDs employing these example principles.

Applying a transparent high refractive index coating layer between theactive circuitry and air or low refractive index packaging layer ontothese devices may further improve their performance. For example, themore gradual transition from the high refractive index of the activecircuitry to air or low refractive index package layer may allow lightto be coupled into or out of the device more effectively, therebyincreasing its efficiency and/or image quality. With higher efficiency,devices can be made more powerful while consuming less energy. Becausesome of these optical devices are made from semiconductor materials thathave refractive indices as high as about 2.5-3.5, the desired refractiveindex of such transparent coating layers is at least 1.8 over the entirevisible region and preferably greater than 1.9.

A polymer would be a good choice for a coating material if itsrefractive index is high enough, at least because of its ease ofprocessing and potential low cost. Unfortunately such a polymer does notexist. The polymer with the world's highest refractive index at presentis believed to have a refractive index of about 1.76 and was developedby Sadayori and Hotta of Nitto Denko.

Inorganic materials that have high refractive indices and hightransparency may be used in certain example embodiments, as maytransition metal oxides such as titanium dioxide or zirconium dioxide(e.g., superlattice nanocrystalline zirconia).

Coatings prepared from solutions such as, for example, metal oxidecontaining materials such as sol-gel coatings and nano-particlecomposites sometimes are brittle and subject to cracking, and theirapplications may be limited by their relatively complicatedmanufacturing process, storage stability, and reliability. Such coatingsgenerally are not well suited for high processing temperatures (e.g., ator above about 400 degrees C.), which is a drawback for mostsemiconducting devices.

Sputtering is another technique currently being used to generate highindex thin films from these and/or other metal oxides. Unfortunately,however, optical device manufacturers may seek other more cost-effectivemethods, as sputtering is generally known to be a relatively higher costand lower throughput approach.

Certain example embodiments involve hybrid coating systems based onpolymeric titanium dioxide and/or polymeric zirconia based systems. Theorganic-inorganic hybrid polymer solution is prepared by first reactingthe titanium alkoxide with a chelating agent to convert the highlyreactive tetra-coordinate titanium species to a less reactivehexa-coordinate species. Other desired polymer components may then beadded to the stabilized titanium containing solution and thoroughlymixed. As a result of the stabilization, the hybrid polymer solution maybe stable at room temperature up to 6 months with negligible change incolor and viscosity. The hybrid polymer solution may be spin-coated orvertical slot coated onto substrates to a desired thickness.

A titanium dioxide rich film was generated by thermally decomposing thehybrid coatings at an elevated temperature of less than about 250degrees C. The resulting dried films may be made as thin as 0.2 um andup to about 4 um or more. Such films may have good transparency and haverefractive indices as high or higher than about 1.90 in the entirevisible region when the cure temperature was 300 degrees C. or higher. Acrack-free film over 300 nm in thickness was obtained with a singlecoating application. Multiple-coating is applicable to obtain a thickerfilm, and no apparent interface was seen from SEM cross-section imagesbetween two consecutive coatings. The hybrid high refractive index filmsare mechanically robust, stable upon exposure to both heat and UVradiation, and may be applicable for a wide variety of opticalapplications. The material is compatible with semiconducting material.

In certain example embodiments, the organic-inorganic hybrid polymer maybe introduced into a laminable medium such as ethylene-vinyl acetate(EVA), silicones, aramids, etc. This would then allow the use of vacuumbonding or de-airing, sometimes without the use of autoclave.

The organic polymers chosen contained multiple hydroxy functionalities.They were so chosen to allow primary or secondary chemical bondingbetween the polymer and the titanium dioxide phase to promote phasecompatibility and a high degree of dispersion. The chelated poly(dibutyltitanate) polymer and the organic polymer are compatible in all orsubstantially all proportions, both in solution and in the cured film,as evidenced by their high transparency and the refractive indexdispersion curves. Typically, an index as high as or higher than 1.9 isobtained at 550 nm for a thickness of 0.4 um. When deposited on anyinorganic light emitting diode, even a film as thin as 0.4 umdramatically improves the light out-coupling from the high refractiveindex material significantly typically in the incremental range of 70%.

FIG. 3 plots the percent transmittance versus wavelength for 0.30 um and0.23 um thick high index matching layers prepared from inorganic-organicpolymer matrix systems in accordance with certain example embodiments.The 0.30 um and 0.23 um thick high index matching layers were depositedon sapphire and quartz substrates, respectively. As can be seen fromFIG. 3, transmission was at least about 80% throughout the visiblespectrum. Certain example embodiments may have yet higher transmissions,e.g., at least about 85%, more preferably at least about 90%, andsometimes even higher.

FIG. 4 is a flowchart illustrating an example process for making ahybrid high refractive index film in accordance with certain exampleembodiments. In step S402, an inorganic-based precursor is provided. Incertain example embodiments, the inorganic-based precursor may be atitanium-based precursor such as, for example, titanium alkoxide, atitanium-based phosphate complex, etc. The inorganic-based precursor maybe deposited directly or indirectly on the LEDs in certain exampleembodiments and/or on a glass substrate. For instance, in certainexample embodiments, a titanium alkoxide based precursor may bedeposited via atomic layer deposition (ALD), a titanium-based phosphatelayer may be printed, etc. Of course, it will be appreciated that otherhigh-index inorganic materials may be used in place of or in addition tothe titanium in certain example embodiments.

In step S404, a chelate may be formed, and an organic component may beadded, together with optional additives. The chelate in certain exampleinstances may be salicylic acid. The organic component in certainexample embodiments may be a resin, silicone, polyimide, polyamide,and/or the like.

Optional additives also may be introduced. For instance, other inorganicmaterials (e.g., in place of or in addition to the titanium-basedprecursor) may be introduced to tune the index of refraction. Indeed,the index of refraction may be adjusted upwardly or downwardly byselective inclusion of zirconia, silica and/or silicates, etc. Lightscattering elements and/or heat dissipating elements also may beintroduced. One example material that functions both as a lighterscattering agent and a heat dissipater is boron nitride. Plasticizersalso may be included in certain example embodiments.

In step S406, the chelated titanium-based precursor and the organiccomponent(s) may be cross-linked to create an organic-inorganic hybridsolution. In one example, titanium alkoxide may be reacted with achelating agent to convert the tetra-coordinate Ti species into a lessreactive hexa-coordinate species, e.g., to create chelated poly(dibutyltitanate). Of course, other titanates may be created and/or used indifferent embodiments of this invention. The hybrid polymer may resultin certain example instances by mixing together the chelatedpoly(dibutyl titanate) with a hydroxy inclusive organic resin. Incertain example embodiments, the organic and inorganic components may beprovided in equal percentages by weight. In certain example embodiments,the organic and inorganic components may be provided in a ratio of 60/40by weight. Of course, other ratios and/or percentages are possible indifferent embodiments of this invention.

The hybrid solution may be quite liquidous in certain exampleembodiments. A liquidous hybrid solution may be advantageous in someexample instances because of its ability to “float” or “swim” betweenLEDs. In such a case, the hybrid solution may be wet applied, verticalslot coated, or otherwise provided to a desired thickness. In certainexample embodiments, however, it may be desirable to provide a moreviscous hybrid laminate (e.g., inorganic and/or other materials includedin an organic binder such as EVA, silicones, aramids, etc.) that can beextruded, for example. A more viscous hybrid laminate may beadvantageous in terms of a “cleaner” or “less messy” application. Theapplication of the hybrid polymer or laminate is shown in step S408.

In step S410, the coated hybrid polymer or laminate is dried and/orcured. The drying and/or curing may help to remove solvents and water,leaving more inorganic material than organic material in certain exampleembodiments. The drying may take place at a first elevated temperatureof less than about 250 degrees C., whereas the curing may take place ata second elevated temperature of greater than or equal to about 300degrees C. Certain example embodiments may include one or both of dryingand curing at these and/or any other suitable temperature.

FIG. 5 shows the basic formulation, cross-linking, and curing stepsinvolved in the FIG. 4 example process. As can be seen in FIG. 5, achelated Ti-based precursor is brought into contact with a resin binderin step S502. In step S504, the resin binder and the chelated Ti-basedprecursor are cross-linked. The solvent is evaporated through a heatingprocess, and the cured film is adhered to a substrate (e.g., a film,hard surface, glass, etc.) in step S506.

Certain example embodiments relate to enhanced scattering of the lightfrom an LED (e.g., ILED) array, e.g., using a scattering layer. Ascattering layer may in certain example instances enhance lightoutcoupling from the ILED array, and/or help achieve non-Lambertianbroad-band scattering useful in achieving a high CRI. Experiments haveshown that a surface texture on a scale of half an internal opticalwavelength may produce a high degree of (and sometimes even complete orsubstantially complete) internal angular randomization of light rays ina semiconductor film. This may be accomplished by natural lithography orany other suitable technique.

The creation of a light scattering layer may include thin film fractalembossing directly or indirectly on the light-emitting region, forexample. This process step in certain example embodiments may take placemay after thin-film transfer and bonding. In certain exampleembodiments, a fractal pattern having a suitable porosity (e.g., 10-30%porosity in certain example instances) for light scattering may belocated, directly or indirectly, on the light-emitting region of theLEDs. Randomness may be inserted into the fractal pattern by anysuitable technique. For example, randomness may be introduced using aself-similar distribution, e.g., by modifying the Sierpinski gasketconstruction by starting with a filled-in unit square, removing arandomly selected quadrant of the square, removing a randomly selectedquadrant of the remaining squares, etc. Another way to add randomness tofractal constructions involves statistical self-similarity, e.g., byscaling each piece of a pattern by a random amount selected from a setrange at each iteration, rather than specifying exact scalings. Randomfractals also may be generated by stochastic processes such as, forexample, trajectories of the Brownian motion, Levy flight, fractallandscapes, the Brownian tree, etc.

Using the above-described and/or other techniques; a template withappropriate features may be generated. The template may then betransferred to the target area. The template may itself accomplish thescattering in certain example embodiments. However, in certain otherexample embodiments, the template may function as a mask and portionsmay be etched away (e.g., photolithographically, by chemicals, etc.) soas to create the desired light-scattering features, and the templateoptionally may be removed. In certain example embodiments, the featuremay be applied to the light emitting diodes or at any suitableinterface. In certain example embodiments, an interface, the chips, thepolymer, semiconductor layers, etc., may be textured, to help achievethe desired light-scattering effects.

Light scattering also may be obtained using polystyrene spheres having a0.2 um radius that are used to coat the surface of the LED in a randomlyclose-packed array. A similar porosity to that described above may beused in such example instances. The polystyrene spheres may be attachedby surface forces in a dipping process, by spin coating, and/or thelike, from an aqueous solution. Such processes may result in the randomlocation of the spheres. The spheres also may act as an etch mask for aCl-assisted Xe+ ion beam etching, of about 10-300 nm, preferably 10-170nm deep into the n+ and/or other AlGaAs layer(s). Plasmas also may beused to perform such etching. These etching techniques also may be usedfor the fractal patterning embodiments described above. Although certainexample embodiments have been described in relation to polystyrenespheres, it will be appreciated that other materials and/or other shapesmay be used in different embodiments of this invention.

Total LED light emission vs. the injection current for enhanced andnon-enhanced AlGaAs diodes is plotted in FIG. 6. Thus, FIG. 6 may bethought of as plotting the luminous efficacy of an AlGaAs diode with andwithout the enhanced light scattering caused by the thin film fractalembossing of certain example embodiments. Calibration may be obtained bythe ratio of photodiode current to LED current, with a small correctionfor photodiode quantum efficiency. The angular distribution of lightfrom these LEDs is Lambertian. The linear fits on FIG. 4 indicate thebroad optimal current range, which may sometimes be limited by heatingat the high end and non-radiative recombination at the low end. Thesquares and diamonds represent two devices drawn from the same wafer andprocessed together up to the final texturing step.

FIG. 7 a is a flowchart illustrating an example process for helping toachieve non-Lambertian broad-band scattering useful in achieving a highCRI using fractal patterns in accordance with certain exampleembodiments. In step S701, a template having a having a random fractalpattern or a fractal pattern having randomness introduced thereto isgenerated. The template is transferred to an area, directly orindirectly, on or of the LED, in step S703. For example, in certainexample embodiments, the area may be on an outermost layer of the LED, asemiconductor layer of the LED, an interface in an LED devicesubassembly, etc. The area is then textured, etched, or embossed in stepS705, using the template. In texturing and/or etching embodiments, thetemplate may be used as a mask (e.g., if formed from a photosensitivebase) for photolithographic patterning, plasma etching, wet etching,and/or the like. In certain example embodiments, the template may beremoved in step S707. However, the template may be left in place indifferent embodiments of the invention. The fabrication of the LEDdevice may be completed in step S709.

FIG. 7 b is a flowchart illustrating an example process for helping toachieve non-Lambertian broad-band scattering useful in achieving a highCRI using scattering elements in accordance with certain exampleembodiments. In step S711, an aqueous solution of nano- or micron-scaleelements is formed. For example, spheres, eye-shaped, cubic, and/orother shaped objects may be used. Such objects may have a major diameteror distance ranging from approximately 0.01-1 um in certain exampleembodiments. The size and number of elements may be selected so as toprovide a target porosity (e.g., along the lines of the above) once theaqueous solution is applied to an area, directly or indirectly, on theLED. The solution may be wet applied, e.g., via spin, roll, dip, slotdie, and/or other coating techniques, in step S713. Such coatingtechniques may help to randomly disperse the elements on the LED, e.g.,at the target porosity. In step S715, the applied solution is optionallydried. In certain example embodiments, the elements may be used as anetch mask such that the LED may be etched or patterned in step S717,e.g., photolithographically, using a plasma, etc. In certain exampleembodiments, the elements may be removed. The fabrication of the LEDdevice may be completed in step S719.

Certain example embodiments also relate to “active cooling” techniquesfor ILED arrays. Such active cooling techniques may help improveefficiency and extend the product lifetime. Chip makers currentlyattempt to reduce the strong parasitic absorption at the electrodes,which is a known issue in all LEDs, by employing an LED design that useslateral injection and depends on current crowding. The diode current iscrowded into a central region between the two ohmic contacts, butreasonably distant from either contact. This design approach reducesparasitic optical absorption at the ohmic contact but also unfortunatelyexacerbates localized heating.

The use of LEDs (e.g., InGaN, AlGaAs, and/or the like) in solid-statelighting and other high-lumen applications would benefit from thedevelopment of LEDs with optical output much greater than that achievedwith traditional LEDs. A conventional InGaN LED has a 350 micron chip,with a semi-transparent current spreading p-contact, and is typicallypackaged in a 5 mm lamp. As explained above, light extraction efficiencyis poor because of light absorption in the semi-transparent contact. Inaddition, the high thermal resistance of the 5 mm lamp (150 degrees C/W)limits the maximum drive current. Consequently, the optical power andlumen outputs are rather low.

In contrast to the conventional packaging of the InGaN LED in an epi-upconfiguration, certain example embodiments involve flip chip packagingof the LED in an epi-down configuration. This example configuration mayhelp to reduce the thermal resistance of the LED. This exampleconfiguration also may in certain example instances enable the LED to bedriven at higher currents. Calculations show that the use of activethermoelectric cooling without replacing the semi-transparent contactwith a reflecting p-contact and use of the flip chip geometryadvantageously results in an increase in the optical extractionefficiency of about 160-300%. These are superior results compared toconventional outputs. Furthermore, in example embodiments that implementactive cooling techniques of the kind the same as or similar to thosedescribed herein, the size of the LED and/or the LED drive current maybe further increased. This advantageously results in even greaterincreases in the optical power and lumen output.

FIG. 8 is a cross-sectional view of a flat ILED matrix laminate inaccordance with certain example embodiments. The FIG. 8 assemblyincludes first and second glass substrates 802 and 804. The firstsubstrate 802 may be thought of as being a superstrate in certainexample embodiments. A high index laminate 806 is supported by thesuperstrate first substrate 802. In certain example embodiments, thelaminate 806 may be formed from the organic-inorganic hybrid materialdescribed above, e.g., that has been extruded. The inner surface 806 aof the laminate 806 may be textured in certain example instances. Incertain example embodiments, the laminate 806 laminates together thefirst and second substrates 802 and 804.

A low index insulator 808 may be supported by second substrate 804. Thelow index insulator 808 in certain example embodiments may be a lowindex version of the organic-inorganic hybrid material described above,e.g., that has been extruded. Thus, in certain example embodiments, thelaminate 806 and the low index insulator 808 may be formed from similarhybrid organic-inorganic materials, provided that their respectiveindices of refraction are tuned for their respective purposes. Incertain example embodiments, the laminate 806 may have a high index ofrefraction, e.g., at least about 1.7, more preferably at least about1.8, and sometimes even as high or higher than 1.9, and the insulator808 may have a low index of refraction, e.g., lower than about 1.8, morepreferably lower than about 1.7, and still more preferably as low as orlower than 1.6-1.65.

A high index layer 812 may be disposed between the laminate 806 and theflexible PCB that supports the LEDs 810. Flexible PCBs suitable forcertain example embodiments may be manufactured or provided by Minco.The high index layer 812 may be an inorganic layer, e.g., of titaniumoxide (e.g., TiO₂ or other suitable stoichiometry), zirconium oxide(e.g., ZrO₂ or other suitable stoichiometry), etc. In certain exampleembodiments, the high index layer 812 may be formed from the hybridorganic-inorganic material described above. However, most or all of theorganic elements may be removed therefrom while in the liquid state oronce at least initially applied (e.g., by drying and/or curing at one ormore elevated temperatures) in certain example instances, e.g., toincrease the index of refraction yet further. In certain exampleembodiments, the material may be wet applied or slot die coated so thatthe liquidous material fills the gaps between adjacent LED componentsand forms a good contact against the flexible PCB 810 with the LEDsdisposed thereon. The surface of the inorganic layer 812 may be texturedin certain example embodiments. In certain example embodiments, one ormore of the laminate 806, insulator layer 808, and high index layer 812may be formed from the organic-inorganic hybrid material (or pluralrespective versions thereof), with each layer having its index tuned byvirtue of the additives in the hybrid solution.

A mirror 814 may be disposed between the insulator 808 and the secondsubstrate 804 in certain example embodiments. The mirror 814 in certainexample instances may comprise a plurality of thin film layers such as,for example, Sn, Ag (e.g., about 1000 angstroms thick), and Cu (about350 angstroms thick), in that order moving away from the secondsubstrate 804. Of course, other materials may be used in place of or inaddition to the example materials listed herein. Other types of mirrorsalso may be used in different example embodiments of this invention. Themirror 814 advantageously may act as a heat sync, thereby helping toimprove the performance of the LEDs in the assembly.

One or more optional layers may be provided on the superstrate glass802. In certain example embodiments, a CRI matching layer 816 may beprovided on the superstrate glass 802. The CRI matching layer maycomprise Cd-based materials such as, for example, CdTe nano-crystals; amatrix of quantum dots; etc. In certain example embodiments, a diffuserand/or antireflective (AR) composite layer may be provided on thesuperstrate glass 802. The AR layer may be a three-layer AR coating incertain example embodiments. See, for example, U.S. application Ser. No.12/923,146, the entire contents of which are hereby incorporated hereinby reference.

In certain example embodiments, phosphors may be embedded in or disposedin a layer on the superstrate glass 802. UV radiation from the LEDs maycause the phosphors to emit light.

In certain example embodiments, a first, thin (e.g., 1 mm thick)low-iron glass substrate may be provided. An anode layer including atransparent conductive coating (TCC) may be blanket coated thereon,e.g., via a wet application in certain example embodiments. It may beadvantageous in certain example instances to use an ion beam toplanarize the OCLS in certain example instances. The blanket anode layermay be laser patterned into the appropriate circuitry. An out-couplinglayer stack (OCLS) used for index matching to the TCC may be interposedbetween the first glass substrate and the anode layer. The patternedanode layer may be encapsulated in certain example embodiments, e.g.,using a heat conductive resin layer of the type described herein. Asindicated above, this may help address the internal junction temperatureof the LEDs, thereby improving efficiency and providing an allsolid-state (or substantially all-solid state) intermediate article orfinished product. A second glass substrate may support a mirror coating(e.g., an Al or Cu mirror coating) in certain example embodiments. Thesubstrate may be etched to form holes, and a dessicant may be insertedinto such holes. OLEDs and/or ILEDs may be used in such an examplearrangement. In certain example embodiments, the location of the anodeand the cathode may be interchanged.

FIG. 9 is an illustrative ILED structure based on AlGaAs in accordancewith certain example embodiments. The ILED structure shown in FIG. 9includes a plurality of layers. The layers may include, in order movingaway from the second substrate 804, a p+ layer 902 of or includingAlGaAs (e.g., that is about 0.3 um thick), a p 904 layer of or includingGaAs (e.g., that is about 0.2 um thick), an n layer 906 of or includingAlGaAs (e.g., that is about 0.04 um thick), an n+ layer 908 of orincluding AlGaAs (e.g., that is about 0.4 um thick), and/or an n+ layerof GaAs (e.g., that is about 0.03 um thick). A p-contact 910 may beprovided on an in contact with the p layer 902 in certain exampleembodiments, and an n-contact 912 may be provided as an uppermost layeron and in contact with one or more n+ layers. As indicated above, one ormore of the n− and/or other layers may be roughened or etched in certainexample embodiments. Also as indicated above, structuring, etching,patterning, and/or the like may be performed at the wafer level incertain example embodiments. Although FIG. 9 shows an AlGaAs-type ILED,it will be appreciated that AlGaN heterostructures may be used indifferent embodiments of this invention.

As alluded to above, the inventors of the instant application haverealized that the efficiency of LED lighting systems may be increased byproviding advanced cooling techniques and that one to accomplish this isthrough the use of thermoelectric cells. Thermoelectric cells rely onthe thermoelectric effect, which generally refers to the conversion oftemperature differences to electric voltage and vice versa. In suchsystems, at the atomic scale, an applied temperature gradient causescharged carriers (e.g., electrons or electron holes) in the material todiffuse from the hot side to the cold side. Thus, a thermoelectricdevice creates a voltage when there is a different temperature on eachside. This effect thus can be used to generate electricity. Certainexample embodiments provide techniques for improving the performance ofLED-based arrays using thermoelectric (TE) modules in conjunction withsuper-insulating, yet optically transmissive, vacuum insulated glass(VIG) unit technologies.

In certain example embodiments, a vacuum insulated glazing (VIG) unit isused as a medium of high thermal resistance (R>12) to housethermoelectric junctions arrays, which are electrically in series andthermally in parallel, on the side facing the sun. According to certainexample embodiments, the R-value preferably is at least 10, morepreferably at least 12, and possibly even higher. High R-values such asthese are currently achievable in VIG units manufactured by the assigneeof the instant invention. Such units generally incorporate fired pillarsand low-E coatings. Of course, a typical argon- and/or xenon-filled IGunit provides an R-value of about 4, and may be used in connection withcertain example embodiments provided that the TE coefficient of merit Zis increased to a suitable level, e.g., as discussed in greater detailbelow. In any event, an R-value of 10 will provide a delta T of about400 degrees C., and an R-value of about 12 will provide a delta T ofabout 600 degrees C.

The number of junctions per unit area preferably is provided at a levelsuch that the fill factor is less than 20%. As is known, fill factorrefers to the ratio (given as percent) of the actual maximum obtainablepower to the theoretical power. Of course, it will be appreciated thatthe fill factor may be balanced with the Z-value, similar to as notedabove. Thus, where the Z-value is greater than or equal to about 10, thefill factor may be reduced to less than or equal to about 10%.

According to certain example embodiments, the VIG unit may servemultiple purposes. For example, the VIG unit may provide a support forthe TE junctions, which may be integrated within the VIG. As anotherexample, the VIG unit may provide for very large temperaturedifferentials between the hot and cold junctions via the inclusion ofthe TE devices within the VIG unit itself. The large delta T, in turn,may help increase the TE efficiency substantially. As still anotherexample, the VIG unit may provide support for flip-chip or otherwisemounted LEDs. As still another example, the VIG unit may help thermallyinsulate the LED devices and reduce the likelihood of the LED fromreaching temperatures that will degrade its operational efficiency.

FIG. 10 is a cross-sectional view demonstrating illustrative activecooling techniques for a flip-chip mounted LED array usingthermoelectric modules in accordance with certain example embodiments.Similar to conventional VIG units, the FIG. 10 example embodimentincludes an outer substrate 1002 and an inner substrate 1004. One orboth of the outer and inner substrates 1002 and 1004 may be glasssubstrates in certain example embodiments of this invention. Thesubstrates are provided substantially parallel, spaced apart relation toone another, and a plurality of pillars 1006 help maintain the distancebetween the outer and inner substrates 1002 and 1004. The pillars 1006may be sapphire pillars in certain example embodiments of thisinvention. An edge seal 1008 is provided around the periphery tohermetically seal the VIG unit, e.g., so that a the cavity between theouter and inner substrates 1002 and 1004 may be evacuated to a pressureless than atmospheric and/or filled with a gas or gasses (such as, forexample, argon, xenon, and/or the like). The outer and inner substrates1002 and 1004 may be the same or different sizes in differentembodiments of this invention.

Each thermoelectric module includes an n-leg 1010 a and a p-leg 1010 band may be made of any suitable material. For example, thethermoelectric module may be bismuth-based (e.g., Bi₂Te₃, Bi₂Se₃, etc.),skutterudite materials (e.g., in the form of (Co,Ni,Fe)(P,Sb,As)₃ or thelike), oxides (e.g., (SrTiO₃)_(n)(SrO)_(m) or the like), etc. Thethermoelectric material may be doped in certain example embodiments.When the TE material is doped, for example, the doping may be gradedsuch that the doping is higher proximate to the hot junction.

The n-leg 1010 a and a p-leg 1010 b of the modules may be connected by aconductor 1012, sometimes referred to as a blackened conductor becauseof the material used therein, even though light may still be transmittedtherethrough. The conductor 1012 may in certain example embodiments be acopper-based material (Cu, CuO, etc.), a frit (e.g., of carbon blacksuch as DAG or the like), a CNT-based ink, etc. The thermoelectricmodules may be screen printed in certain example embodiments of thisinvention. The size of each module may be selected in conjunction withthe desired fill factor. When a 20% fill factor is used, for example, asubstantially square approximately 1″×1″ module size may be used,although other sizes and/or shapes are possible in connection with thisand/or other fill factors. In certain example embodiments, the pillars1006 may be placed following the screen printing of the TE materials.

In certain example embodiments, the TE modules are not in direct contactwith the inner substrate 1004. Instead, in certain example embodiments,a bus bar 1014 is provided between the inner surface of the innersubstrate 1004 (surface 3) and the thermoelectric materials. This busbar may be transparent and thus may be of or include any suitablematerial such as, for example, a transparent conductive coating of orincluding Ag, ITO, AZO, indium-galluim-oxide, etc. The conductivecoating may also be a CNT-based, graphene based, etc. CNT-basedconductive coatings/devices and methods of making the same are disclosedin, for example, U.S. application Ser. No. 12/659,352, the disclosure ofwhich is hereby incorporated herein by reference, and graphene-basedconductive coatings/devices and methods of making the same are disclosedin, for example, U.S. application Ser. No. 12/654,269, the disclosure ofwhich is hereby incorporated herein by reference. To help facilitate thetransfer of power, a silver or other conductive frit (not shown) may beprovided proximate to the edge of the VIG unit and in direct or indirectcontact with the bus bar 1014. In certain example embodiments, the edgeseal 1008 itself may be formed from a conductive material and thus mayserve as the appropriate connection.

Flip-chip mounted LEDs 1016 may be disposed on the conductors 1012. Morespecific details of the flip-chip mounted LEDs 1016 are provided below,e.g., in connection with FIG. 12.

FIG. 11 is a plan view of an ILED structure electrically connected inseries and thermally connected in parallel in accordance with certainexample embodiments. The TE modules are electrically connected in serialsuch that the n-leg in a first module is connected to the p-leg in asecond module (or vice versa), etc., until the end of a row or column,and then adjacent columns or rows are connected, and the pattern repeatsalong the new row. The TE modules are thermally connected in parallelbecause they are all located within the cavity of the VIG unit. Eachside of the VIG unit contains at least one positive terminal and atleast one negative terminal. The silver frit discussed above thus mayprovide around substantially the entire periphery of the VIG unit, atlocations where the terminals are to be provided, etc. As calla be seenfrom FIG. 11, the TE modules occupy space such that predetermined fillfactor is met (in this example case, about 20%).

Further details regarding TE modules can be found, for example, in U.S.application Ser. No. 12/801,257, the entire contents of which is herebyincorporated herein by reference.

FIG. 12 is a cross-sectional view of a flip-chip sub-mount wafer inaccordance with certain example embodiments. In general, flip-chipmounting is one type of mounting used for semiconductor devices, such asintegrated circuit (IC) chips, which reduces the need for wire bonds.The final wafer processing step deposits solder bumps on chip pads,which connect directly to the associated external circuitry. Theprocessing of a flip-chip is similar to conventional IC fabrication.Near the end of the process of manufacturing a flip-chip, attachmentpads are metalized to make them more suitable for soldering. Thismetalizing typically includes several treatments. A small solder dot isdeposited on each of the pads. The chips are cut out of the wafer, asconventional. Additional processing generally is not required, andgenerally there is no mechanical carrier at all. When a flip-chip isattached to a circuit, it is inverted to bring the solder dots down ontoconnectors on the underlying electronics or circuit board. The solder isthen re-melted to produce an electrical connection. This leaves a smallspace between the chip's circuitry and the underlying mounting. In mostcases an electrically-insulating adhesive is then used to provide astronger mechanical connection, provide a heat bridge, and to ensure thesolder joints are not stressed due to differential heating of the chipand the rest of the system. The resulting completed assembly is muchsmaller than a traditional carrier-based system. The chip sits on thecircuit board, and is much smaller than the carrier both in area andheight.

Referring once again to FIG. 12, a substrate 1202 is provided, e.g., ascut from a wafer. The substrate 1202 in certain example embodiments maybe sapphire, quartz, or any other suitable material. An outer surface1202 a may be textured, patterned, embossed, or the like, in certainexample instances, e.g., as described above. The substrate 1202 maysupport a plurality of thin film layers including, for example, ann-type GaN layer 1204. The n-type GaN layer 1204 may, in turn, supportn-contacts 1206, e.g., at the periphery thereof. In the center of then-type GaN layer 1204 in certain example arrangements, a plurality offurther thin-film and/or other layers may be provided. For example, anactive region 1208, a p-type

GaN layer 1210, and a p- contact 1212 may be provided. The n-contacts1206 and the p-contact 1212 may be connected to a submount wafer 1218 bysolder balls 1214 and 1216, respectively, in certain exampleembodiments. In certain example embodiments, the GaN and/or other layersmay be InGaN layers.

FIG. 13 is an example VIG incorporating LEDs in accordance with anexample embodiment. FIG. 13 is similar to FIG. 10, in that FIG. 13includes first and second substantially parallel spaced apart glasssubstrates 1302 and 1304. A plurality of pillars 1306 helps maintain thefirst and second substrates 1302 and 1304 in proper orientation, and anedge seal 1308 hermetically seals the cavity 1310. In any event, aplurality of LEDs 1312 is supported by the second substrate 1304 incertain example embodiments.

The cavity 1310 may be evacuated to a pressure less than atmospheric incertain example embodiments. In certain example embodiments, the cavity1310 may be “back filled” with a suitable gas (e.g., an inert gassuch-as, for example, Ar, Kr, Xe, Ne, He, etc.). He has been found to beparticularly advantageous in connection with certain example embodimentsbecause it is a good heat transfer material. A VIG that includes He, forexample, therefore may be provided in place of thermocouples in certainexample instances.

The above-described techniques may be used in connection with the FIG.13 example embodiment. For instance, a high index layer may be providedover the LEDs. It may in certain example instances be advantageous toremove all or substantially all of the organic material from theabove-described hybrid layer (e.g., upon curing) in connection with theFIG. 13 example embodiment. Embossing, patterning, and/or othertechniques also may be used. Although not shown, the LEDs 1312 may beprovided on a flexible PCB (not shown), e.g., the LEDs 1312 may beflip-chip mounted thereto in certain example instances. In certainexample embodiments, the LEDs 1312 may be embedded in a laminate (notshown).

Vacuum insulating glass (VIG) units are known in the art. For example,see U.S. Pat. Nos. 5,664,395; 5,657,607; and 5,902,652, U.S. PublicationNos. 2009/0151854; 2009/0151855; 2009/0151853; 2009/0155499;2009/0155500, and U.S. application Ser. Nos. 12/453,220 and 12/453,221,the disclosures of which are all hereby incorporated herein byreference. The edge seal, pump-out, and/or othertechniques/configurations of these references may be used in connectionwith certain embodiments of this invention.

The techniques described herein advantageously may help to provideimproved colormetrics. As will be appreciated, when LEDs arepre-packaged and/or purchased in bulk, the colormetrics may differ.Certain example techniques described herein may help to reduce (andsometimes even eliminate) such issues.

Certain example embodiments have been described in relation to lightingproducts. However, the techniques described herein may be used inconnection with other applications such as, for example, displayproducts (e.g., for backlights in LCD and/or other flat panel designs),mobile devices, decorative elements (e.g., windows, doors, skylights,sidelights, etc.), etc.

In certain example embodiments, the Lambertian or non-Lambertian lightsources may be disposed on flat, substantially flat, or curvedsubstrates. Thus, it will be appreciated that the lighting devices mayinclude such flat, substantially flat, or curved substrates.

As used herein, the terms “on,” “supported by,” and the like should notbe interpreted to mean that two elements are directly adjacent to oneanother unless explicitly stated. In other words, a first layer may besaid to be “on” or “supported by” a second layer, even if there are oneor more layers therebetween.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiment, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. A device, comprising: a first substrate; a mirrorsupported by the first substrate; a printed circuit board supporting aplurality of light emitting diodes (LEDs); a second substrate; alaminate supported by a first major surface of the second substrate thatfaces the printed circuit board supporting the plurality of LEDs,wherein the laminate is formed from a first organic-inorganic hybridsolution, the laminate having an index of refraction of at least about1.8; and a layer of or including inorganic material having an index ofrefraction of at least about 1.8, the layer of or including inorganicmaterial being disposed between the printed circuit board supporting theplurality of LEDs and the laminate.
 2. The device of claim 1, wherein amajor surface of the laminate closest the printed circuit boardsupporting the plurality of LEDs is textured.
 3. The device of claim 1,further comprising an insulator layer interposed between the mirror andthe printed circuit board supporting the plurality of LEDs.
 4. Thedevice of claim 3, wherein the insulator layer is formed from a secondorganic-inorganic hybrid solution, the insulator layer having arefractive index lower than about 1.8.
 5. The device of claim 1, furthercomprising a CRI matching layer disposed on a second major surface ofthe second substrate.
 6. The device of claim 5, wherein the CRI matchinglayer comprises CdTe nano-crystals.
 7. The device of claim 1, whereinthe printed circuit board is a flexible printed circuit board.
 8. Thedevice of claim 7, wherein the LEDs are flip-chip mounted to theflexible printed circuit board.
 9. A device, comprising: a first glasssubstrate; a thin-film mirror coating supported by the first substrate;a flexible printed circuit (FPC) supporting a plurality of lightemitting diodes (LEDs) flip-chip mounted thereto; a second glasssubstrate; a laminate supported by a first major surface of the secondsubstrate that faces the flexible printed circuit supporting theplurality of LEDs, the laminate laminating together the first and secondsubstrates; and a layer of or including inorganic material having anindex of refraction of at least 1.8, the layer of or including inorganicmaterial being disposed between the flexible printed circuit supportingthe plurality of LEDs and the laminate.
 10. The device of claim 9,wherein the laminate is formed from a first organic-inorganic hybridsolution, the laminate having an index of refraction of at least about1.8.
 11. The device of claim 9, wherein a major surface of the laminateclosest the FPC is textured.
 12. The device of claim 9, furthercomprising an insulator layer interposed between the mirror and the FPC.13. The device of claim 12, wherein the insulator layer is formed froman organic-inorganic hybrid solution, the insulator layer having arefractive index lower than about 1.8.
 14. The device of claim 9,wherein the layer of or including inorganic material is formed from anorganic-inorganic hybrid solution.
 15. A device, comprising: a firstglass substrate; a thin-film mirror coating supported by the firstsubstrate; a flexible printed circuit (FPC) supporting a plurality oflight emitting diodes (LEDs) flip-chip mounted thereto; a polymer-basedinsulator layer interposed between the mirror and the FPC, the insulatorlayer being formed from a first organic-inorganic hybrid solution; asecond glass substrate; a laminate supported by a first major surface ofthe second substrate that faces the flexible printed circuit (FPC)supporting the plurality of LEDs, the laminate laminating together thefirst and second substrates; and an inorganic layer provided between thelaminate and the FPC, the inorganic layer being formed from anorganic-inorganic hybrid solution.
 16. The device of claim 15, whereinthe laminate is formed from a second organic-inorganic hybrid solution,and wherein a major surface of the laminate closest the FPC is textured.17. The device of claim 15, wherein a major surface of the inorganiclayer farthest from the FPC is textured.
 18. The device of claim 1,wherein the layer of or including inorganic material having an index ofrefraction of at least about 1.8 comprises an oxide of titanium.
 19. Thedevice of claim 1, wherein the layer of or including inorganic materialhaving an index of refraction of at least about 1.8 comprises an oxideof zirconium.
 20. The device of claim 1, wherein the layer of orincluding inorganic material having an index of refraction of at leastabout 1.8 consists essentially of metal oxide.
 21. The device of claim1, wherein the layer of or including inorganic material has an index ofrefraction of at least about 1.8 consists essentially of metal oxide.22. The device of claim 1, wherein the layer of or including inorganicmaterial consists essentially of inortganic material.